Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.17, when the trusted_proxies option is configured, heimdall extracts client IP addresses from the Forwarded (for= parameter) and X-Forwarded-For headers and exposes them as Request.ClientIPAddresses to the rule pipeline. However, extracted values are not validated to be syntactically valid IP addresses. Arbitrary strings, malformed IP literals, and RFC 7239 unknown values and obfuscated identifiers are accepted without further checks. In addition, the Forwarded header parser splits on , and ; without accounting for RFC 7239 quoted strings, which can cause a single quoted value to be parsed as multiple entries, with fragments — including trailing quote characters — treated as independent addresses. This issue has been patched in version 0.17.17.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-38x9-25wx-7fg2 | Heimdall: IP Spoofing via Unvalidated Forwarding Headers |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 23 Oct 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.17, when the trusted_proxies option is configured, heimdall extracts client IP addresses from the Forwarded (for= parameter) and X-Forwarded-For headers and exposes them as Request.ClientIPAddresses to the rule pipeline. However, extracted values are not validated to be syntactically valid IP addresses. Arbitrary strings, malformed IP literals, and RFC 7239 unknown values and obfuscated identifiers are accepted without further checks. In addition, the Forwarded header parser splits on , and ; without accounting for RFC 7239 quoted strings, which can cause a single quoted value to be parsed as multiple entries, with fragments — including trailing quote characters — treated as independent addresses. This issue has been patched in version 0.17.17. | |
| Title | Heimdall: IP Spoofing via Unvalidated Forwarding Headers | |
| Weaknesses | CWE-116 CWE-20 CWE-290 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-23T12:28:09.427Z
Reserved: 2026-06-24T02:00:46.801Z
Link: CVE-2026-57210
No data.
Status : Received
Published: 2026-10-23T13:17:11.847
Modified: 2026-10-23T13:17:11.847
Link: CVE-2026-57210
No data.
OpenCVE Enrichment
No data.
Github GHSA